The present invention relates to an image reading apparatus called a scanner which is incorporated in a copying machine, a facsimile machine and others to be used.
In many cases, an image reading apparatus has been composed of an image reading apparatus main body provided thereon with a sensor such as CCD which reads images on an original and an original conveyance apparatus conveying an original to a reading position, both of which are formed as separate units so that the original conveyance apparatus is mounted on the image reading apparatus main body. Under the aforesaid condition, two positioning pins have been provided on the image reading apparatus main body, and holes corresponding to these positioning pins have been provided on the original conveyance apparatus so that the original conveyance apparatus may be positioned on the image reading apparatus by making the positioning pins to fit in the holes on the original conveyance apparatus. Then, the original conveyance apparatus thus positioned has been fixed to that position by means of screws.
However, in the conventional method for positioning and fixing the original conveyance apparatus stated above, an error in positioning of the original conveyance apparatus has been caused by an error and improper fitting conditions of parts used for mounting the original conveyance apparatus on the image reading apparatus, and thereby a phenomenon which is not preferable for image reading has been caused. This phenomenon will be explained as follows, referring to FIGS. 1 and 2.
In the image reading apparatus wherein the original conveyance apparatus which conveys original OR to the exposure position is formed as a unit for the original conveyance apparatus main body on which line sensor SE that reads images of the original to be mounted thereon, when an angle for positioning the original conveyance apparatus on the image reading apparatus is deviated, the line sensor SE is arranged to be oblique to the original OR by deviation angle a from the direction perpendicular to the conveyance direction for the original as shown in FIG. 1, and moves relatively in the arrowed direction X for scanning.
As a result of the scanning, a rectangle on the original having longitudinal sides V and lateral sides H is read as an image deformed to be a parallelogram having oblique sides V1 inclined from the longitudinal side V by inclination angle a and lateral sides H and H1 (incidentally, the deviation angle a is shown to be greater than an actual angle).
As measures for the phenomenon stated above, there have so far been taken steps while watching inclination of the image reproduced through image reading, wherein each of screws at two points where the original conveyance apparatus is fixed on the image reading apparatus is loosened, and the position of the original conveyance apparatus is adjusted at each of the two points so that the original conveyance apparatus may be mounted and fixed again.
In this method of mounting an original conveyance apparatus, however, there have been caused difficulties in the steps to adjust the position of the original conveyance apparatus on the image reading apparatus main body and to establish the position, resulting in problems of time-consuming works.
A type of the image reading apparatus includes an apparatus of an optical system movement exposure type wherein an optical system reads images on an original stationary at an image reading position while the optical system is moving, and an apparatus of an original movement exposure type wherein images on an original moving on the image reading position are read by a fixed optical system.
In the case of the apparatus of a scanning exposure type, when the original conveyance apparatus is mounted with a deviated angle on the image reading apparatus incorrectly in terms of a mounting angle, an image to be outputted appears to be an inclined image. In the case of an apparatus wherein an original is stopped when its end portion hits a stopper plate, it is naturally possible to correct the inclination of the original to a certain degree by adjusting an amount of the hitting, which, however, requires the correcting means.
In the case of the apparatus of a synchronization exposure type, when the original conveyance apparatus is mounted with a deviated angle on the image reading apparatus incorrectly in terms of a mounting angle, an image to be outputted has an inclination angle agreeing with the deviated angle and is deformed to be a parallelogram whose side in the main scanning direction is longer than an actual side. Namely, a distorted image is outputted. The distortion of this image is not only a visual problem but also a serious problem in outputting drawings. In addition, it is not possible to adjust an amount of the hitting, which is different from the apparatus of the optical system movement exposure type.
Therefore, the invention can be applied to an apparatus of any type, and it is especially effective for the apparatus of the original movement exposure type.
Therefore, an object of the invention is to solve the problems mentioned above and to provide an image reading apparatus having the mounting structure with which an original conveyance apparatus can be mounted on an image reading apparatus main body easily.
The object of the invention stated above can be attained by an image reading apparatus having an original conveyance apparatus for conveying an original, including: a first mounting member for coupling the original conveyance apparatus to the image reading apparatus so that the original conveyance apparatus is displaceable with respect to the image reading apparatus substantially in a direction perpendicular to a conveyance direction of the original; a second mounting member for coupling the original conveyance apparatus to the image reading apparatus so that the second mounting member serves as a rotation axis when the original conveyance apparatus is displaced in the direction perpendicular to the conveyance direction; and a fixing member for fixing the original conveying member to the image reading apparatus after the original conveyance apparatus has been displaced with respect to the image reading apparatus with the second mounting member serving as the rotation axis.
Further, the object of the invention can be attained as a preferable structure by an image reading apparatus having therein an original conveyance apparatus conveying an original to the reading position and a reading means that reads images of an original under conveyance at the aforesaid reading position, the original conveyance apparatus being formed as a unit separate from the image reading apparatus main body having thereon the reading means and being mounted on the image reading apparatus main body, wherein a first mounting section is provided on one end portion of one side of the original conveyance apparatus and a second mounting section is provided on the other end portion, and the original conveyance apparatus is mounted on the image reading apparatus in a way that the original conveyance apparatus is moved relatively to the image reading apparatus by the first mounting section and the original conveyance apparatus is rotated relatively to the image reading apparatus by the second mounting section, and there is provided a fixing means which fixes the original conveyance apparatus at the position to which the original conveyance apparatus is moved by the first mounting section.